TITLE:
SHRIMP U-Pb and U-Pb Laser Ablation Geochronological on Zircons from Monte Santo Alkaline Intrusive Suite, Westhern Araguaia Belt, Tocantins State, Brazil
AUTHORS:
Rúbia Ribeiro Viana, Gislaine Amorés Battilani
KEYWORDS:
Alkaline Rocks, Shrimp Dating, Tocantins Structural Province, Neoproterozoic, Brazil
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.2 No.3,
June
13,
2014
ABSTRACT: The Monte Santo Alkaline Intrusive Suite
(MSAIS) is an association syenite foid, nepheline syenite and syenite, which
are intruded in metapelites of the Rio do Coco meta-volcanic-sedimentary Sequence,
presenting abundant pegmathoid veins cutting all of them. The ages obtained by
Shrimp (1051 ± 22 Ma, 1048 ± 11 Ma) are very close those younger age obtained
by U-Pb laser ablation (1056 ± 21), beeing interpreted as crystallization age.
These dating reveal also that MSAIS rocks were affected by common succession of
younger events below 550 Ma ago, responsible by the later rocky bodies of
varying composition occurring in the region, including the alkaline pegmatites
hosted in the nepheline syenite of the MSAIS.